The present disclosure herein relates to an optical communication device, and more particularly, to a method of tuning a resonance wavelength of a ring resonator.
According to the miniaturization and high-speed trends of electronic devices, researches are continuing in order to increase the integration density of components which constitute the electronic devices. For the miniaturization and high-speed operation of the electronic devices, a rapid signal transmission between the components is required together with the miniaturization of the components.
As a way of rapid signal transmission between the components, an application of optical communication technologies to electronic devices is being attempted. In the case where the optical communication technologies are applied to the electronic devices, the signal transmission can be performed at higher speed and the disadvantages of a related art signal transmission method such as high resistance, high-heat generation and parasitic capacitance phenomenon, etc., can be mitigated.
The essential optical devices for applying the optical communication technologies to a silicon-based semiconductor chip may include a silicon-based optical switch, an optical modulator, a multiplexer (MUX)/demultiplexer (DEMUX) filter and the like, in addition to a light source and an optical detector. Although the roles and functions of the optical switch, the optical modulator and the MUX/DEMUX filter among these are different, there are many cases where the core manufacturing technologies are shared or the same device is applied differently. For example, in the case of a ring resonator, it can be applied to all of the above three devices such that active researches are in progress.
Particularly, in order to achieve a multi-core central processing unit (CPU) which is one of the goals of silicon photonics research, a common opinion of scholars is that the following key difficult problems of a ring resonator should be solved. First, the statistical errors of resonance wavelength, which essentially occurs during the manufacturing process of the ring resonator, should be minimized. Second, a tuning method should exist to match the resonance wavelengths, when the resonance wavelengths between more than two ring resonators should be matched to each other in the semiconductor chip with a plurality of ring resonators. Third, a photolithography process is able to manufacture the minimum gap between a ring waveguide and a bus line or a ring waveguide and a ring waveguide.